1. Field of the Invention
The invention relates to a continuous casting mold for casting strands, preferably of steel, composed of mold plates and water boxes which are connected to each other and between which a water cooling system is constructed by means of water conduits, wherein the water conduits are arranged in the side of the water box facing the mold plate and not in the mold plate.
2. Description of the Related Art
Mold plates--preferably composed of copper for continuously casting slabs, thin slabs, blooms and sections--are cooled on the rear side thereof with water and are screwed onto a steel water box.
For example, in thin slab molds, the water is conducted through conduits having a width of about 5 mm from the outlet of the mold (bottom) vertically in the direction of the casting meniscus toward the upper edge of the mold. The water is conducted with a pressure of between 5 and 15 bars and flow velocities of 5 to 15 m/s through the water conduits in order to be able to absorb and convey away the thermalflux of up to 4 MW/m.sup.2 at the phase boundary copper/water without an interference of the heat transfer by the formation of bubbles.
As a rule, these water conduits are worked into the copper plate on the side of the copper plate facing the water. This is done in mechanical workshops with NC-controlled machine tools which require a lot of time for this work and are very expensive.
It must also be noted that, especially in the case of thin slabs, molds according to DE 34 00 220 C2--with a concave shape on the side facing the steel or a convex shape on the side facing the water--the manufacture of water conduits requires more complicated machinery and higher costs than is the case in copper plates which have flat parallel sides and which are used in conventional slab molds.
In addition, in view of the service life of the copper plates which are to be considered wear parts, the provision of the water conduits is not useful economically.
Japanese document JP-A-61 146 444 shows a mold plate for the continuous casting of strands composed of steel. The mold plate is of sandwich construction and is composed of a copper plate for guiding the cast strand, wherein the copper plate is in connection with a support plate through a screw connection. Water conduits are arranged in the support plate. For connecting the copper plate to the support plate, increased thickness portions are provided on the side of the copper plate facing the support plate which engage in corresponding indentations in the support plate. Screws for tightly connecting the copper plate and the support plate are screwed into the increased thickness portions. The water conduits are arranged in the support plate and not in the copper plate.
A copper plate in sandwich construction is shown in PCT document WO-A-9521036, particularly FIG. 11. A copper plate on which the cast strand is guided is located on a steel plate. Cooling conduits are arranged in the steel plate and not in the copper plate. The cooling conduits are covered by the copper plate and the connection between the steel plate and the copper plate is effected by means of a screw connection. Sealing between the steel plate and the copper plate is effected by means of soft solder.